In recent years, as a necessity for high-precision positional information has been highly enhanced, the positioning technology of specifying a position of a mobile radio appliance, which is typified by a positioning technology employing a GPS satellite, is now being studied/developed vigorously.
As one of the positioning techniques, there exists the technique of positioning a reference point, being a position of a fixed radio appliance that is on a footing of being able to position a mobile radio appliance by transmitting or receiving a radio signal. For this, the positioning technique of the reference point can be easily introduced because a usual relation with a wireless communication system can be utilized. For this reason, in recent years, the reference point positioning system has been introduced as one of value-added services of a cellular net or a wireless LAN.
On the other hand, as a high-precision positioning system employing the positioning of the reference point, there exist the systems described in Non-patent documents 1 to 3. Each of theses system is a system aiming for the positioning for which an infrastructure is laid out.
As a general condition required for the positioning system, there exist a positioning accuracy and a positioning area. One example of the positioning accuracy and the positioning area is shown in FIG. 36 and FIG. 37, respectively. The so-called positioning accuracy, which is a precision of a position of the mobile radio appliance that is specified by the positioning system, is an area size 1053 of an area 1052 in which a radio signal is transmittable to, or receivable from, or transmittable/receivable to/from one fixed radio appliance 1051, as shown in an example of FIG. 36. Further, the so-called positioning area, which is an area in which a radio signal is transmittable to, or receivable from, or transmittable/receivable to/from at least one fixed radio appliance or more, and yet a position of the mobile radio appliance can be specified, is an area 1057 in which a signal is transmittable to, or receivable from, or transmittable/receivable to/from at least one fixed radio appliance or more (three fixed radio appliances 1054 to 1056 in the figure) as shown in an example of FIG. 37.
Conventionally, the design of the communication system as disclosed in patent document 1 has been applied for the system for positioning the reference point introduced as an added value of a communication infrastructure. In the design of the communication system, its system is designed so that no non-covered area is generated also in a case where noise or interference becomes maximized and yet a communication distance becomes minimized because it is of importance to two-dimensionally cover the area in which the communication service is provided. For this reason, the system for positioning the reference point introduced into a cellular net or a wireless LAN, of which the area is identical to the communication area of the cellular net or the wireless LAN, is extremely bad in terms of the positioning accuracy because it is designed with a concept of the communication area that desirably covers the area as widely as possible.    [Patent document 1] JP-3515457B “A method of designing an arrangement of base stations of a radio communication system”    [Non-Patent document 1] Ishii et al.; “A Proposal of Hybrid Wireless LAN positioning system (2);” Proceedings of the 2004 IEICE General Conference, B-5-225    [Non-Patent document 2] Tsubaki et al.; “Tracking System using RFID Tags;” Proceedings of the 2003 IEICE General Conference, B-15-11    [Non-Patent document 3] Yoneyama et al.; “Allocating system in Doors in the Use of Bluetooth;” Proceedings of the 2003 IEICE General Conference, B-15-9